Hi Arnd,
Thank you for the patch.
On Monday, 4 December 2017 16:44:23 EET Arnd Bergmann wrote:
gcc-8 -fsanitize-coverage=trace-pc produces a false-positive warning:
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c: In function 'mdp5_plane_mode_set.isra.8': drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c:1053:3: error: 'crtc_x_r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
It's relatively clear from reading the source that this cannot happen, and older compilers get it right. This rearranges the code remove the two affected variables, which reliably avoids the problem.
Signed-off-by: Arnd Bergmann arnd@arndb.de
The patch looks good to me, so
Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
However I think it would also be useful to file a bug report for gcc, especially if older versions got this right.
drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c index be50445f9901..c50449882037 100644 --- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c +++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c @@ -964,8 +964,6 @@ static int mdp5_plane_mode_set(struct drm_plane *plane, uint32_t src_x, src_y; uint32_t src_w, src_h; uint32_t src_img_w, src_img_h;
uint32_t src_x_r;
int crtc_x_r; int ret;
nplanes = fb->format->num_planes;
@@ -1010,9 +1008,6 @@ static int mdp5_plane_mode_set(struct drm_plane *plane, crtc_w /= 2; src_w /= 2; src_img_w /= 2;
crtc_x_r = crtc_x + crtc_w;src_x_r = src_x + src_w;}
ret = calc_scalex_steps(plane, pix_format, src_w, crtc_w, step.x);
@@ -1052,9 +1047,9 @@ static int mdp5_plane_mode_set(struct drm_plane *plane, if (right_hwpipe) mdp5_hwpipe_mode_set(mdp5_kms, right_hwpipe, fb, &step, &pe, config, hdecm, vdecm, hflip, vflip,
crtc_x_r, crtc_y, crtc_w, crtc_h,
crtc_x + crtc_w, crtc_y, crtc_w, crtc_h, src_img_w, src_img_h,
src_x_r, src_y, src_w, src_h);
src_x + src_w, src_y, src_w, src_h);plane->fb = fb;